Combinations of sulfonamides and sulfonamide-potentiators have long been known as antibacterials and have been used extensively for the treatment of bacterial infections in humans and in animals.
However, the sulfonamides and their potentiators have different solubility characteristics. Since a weak acid sulfonamide must be combined in non-stoichiometric amounts with a weak base potentiator, difficulties have been encountered in the preparation of useful pharmaceutically acceptable solutions (e.g., injectable solutions) made by combining these materials.
The solutions prepared by the procedures disclosed in the prior art have not been completely satisfactory. Problems such as solvent compatibility (especially where large quantities of organic solvents were used), precipitation of the active ingredients from the solutions, solution instabilities and processing costs hampered the development of compositions suitable for injection use.
It is an object of this invention, therefore, to provide pharmaceutical compositons, in aqueous form or in a composition readily convertible to aqueous form, which compositions have acceptable solvent compatibility, dissolve sufficiently high concentrations of active material, have physiologically acceptable pHs, are stable and require no expensive adjuvants.